Process of making alloys.



UNITED STATES JOHN T. H. DEMPS TER,

PATEN onnren. f

OBSOHENEGTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PROGESS OF MAKING ALLOYS.

Specification of Letters Patent.

Application filed March. 28,

Patented luly c, 1909.

.1908. Serial No. 423,907.

To all whom it may concern:

Be it known that I, JOHN T. H. DnMPs'rnn, a citizen of the United States, residing at Schenectady, in the county of Schenectady of alloys by a rocess which is simple and at the sametime ends itself to the formation of an alloy in which the composition is accurately and definitely known.

In my revious patent No. 901 ,428, I have describe and claimed a resistance conductor which has valuable roperties adapting it to a variety of uses. his alloy is heatrefractory to an extraordinary degree. It does not easily oxidize when subjected to a prolonged red heat in the atmosphere. It is acid-proof and has high electrical resistivity adaptin it for electric heating and rheostat wor 'lhe slight oxidation which the wire undergoes from prolonged red heat goes on slowly and the oxid is coherent and does not materially change its conductivity. The complositron which I have found very success 1 contains approximately 62 parts nickel 20 parts iron 13parts chromium 5 parts manganese In the melting of this allo it was found that carbon must be exclude from the mixture sincev otherwise the alloy became hard and brittle. It was found moreover that nickel is high in carbon andthat it is therefore necessary to purify the nickel in making up the alloy. Graphite crucibles cannot be used because of the fact that the metals of the alloy will take up carbon. Clay-lined crucibles serve the purpose excepting for the fact that the manganese attacks the clay and exposesthe graphlte. The following recess has been found to operate satisfactori y. In the bottom of a clay-lined graphite crucible is placed an oxid to serve as a decarbonizer. This. oxid may be hematite (Fe,O,). It is- (by weight) i found that about eight ounds of this oxid is necessary for one hun red pounds of alloy.

and when the nickel is melted the heat is run up to promote a vigorous reaction between the ox1d and the carbon. This reaction is shown by the gas bubbles igniting above the slag and burning with a blue flame. When the metal quiets down, the carbon being eliminated, the iron'is added and after this is melted the chromium is added. While the mixture is in a molten condition, care being taken not to excessively heat the metal and burn the lining, the manganese is added in suitable quantities. The mixture is then quickly poured before the manganese attacks the clay lining.

By this. recess I am able to practically eliminate t e carbon from the mixture and obtain an accurately proportioned alloy in a simple manner.

'VVhile I have described my invention in connection with specific metals mixed in certain portions as well as steps of the process taken in a certainway, it should be understood that I do not limit my invention thereto except in so far as it is limited by the see c of the claims annexed hereto.-

hat I claim as new and desire to secure by Letters Patent of the United States, is,

l. The process of producing alloys which consists in melting a quantity of nickel with chromium in suitable proportions, then adding manganese and pouring the mixture before the manganese attacks the clay lining.

2. The process of producingalloys which consists in first de-carbonizing a quantity of nickel in a clay-lined crucible, successively adding other metals in suitable proportions including manganese and then pouring the -mixture before the manganese attacks the clay lining.

3. The process of producing alloys which consists in first de-carbonizing a quantity of nickel ina clay-lined crucible, successively adding chromium and manganese in suitable proportions and then pouring the mixture efore the manganese attacks the clay lining.

In Witness whereof, I have hereunto set my hand this 26th day of March, 1908.

JOHN T. H. DEMPSTER.

Witnesses:

P. H. SMITH, T. I. Tnonrson. 

